ABSTRACT
Hedyotis diffusa and H. corymbosa belong to the genus Hedyotis Linn. in family Rubiaceae. They shared similar heat-clearing and toxin-resolving effects and pharmacological activities, such as anti-cancer activity, and H. diffusa is frequently adulterated or substituted by H. corymbosa in clinical application. But whether they can completely replace with each other or whether the therapeutic effect could be changed after the substitution, is still a problem needs to be resolved. Therefore, the two herbs were compared in terms of the textual research, medical history, mixed use, commercial medicine status, macro-characters, micro-characteristic, chemical compositions and pharmacologic activities, and found that they shared similar macro-characters and micro-characteristic but were obviously different in chemical composition and pharmacologic activities, and now they could be identified quickly and accurately by molecular identification method. Therefore, we suggest that they should be used as two different medicinal materials at this stage.